It is generally agreed that diet plays a large role in controlling the risk of developing cancers and that increased consumption of fruits and vegetables may reduce cancer incidences in humans. The presence of certain minor chemical components in plants may provide a major protection mechanism when delivered to mammalian cells.
Cruciferious vegetables contain phytochemical precursors to potent chemoprotectants especially glucoraphanin and its associated conversion product sulforaphane, that when delivered to mammalian cells trigger carcinogen detoxification mechanisms. In addition to reducing the risk of getting certain cancers, glucoraphanin through its bioactive conversion product sulforphane has recently been shown effective in destroying the organism responsible for causing the majority of stomach ulcers and may provide novel approaches for reducing the risk of developing cardiovascular and ocular diseases. Efforts are being undertaken to gain approval for making label claims on food products either naturally high in these agents or for foods containing added crucifer chemoprotectants. Products containing chemoprotectant additives, although without claims, are already on the market.
Cruciferous vegetables also contain other compounds, such as indole glucosinolates, which are problematic for maintaining good health. Not only are these compounds weak inducers of the carcinogen detoxification system, but also they can induce systems which may bioactivate certain pro-carcinogens. In addition, the breakdown products of indole glucosinolates formed in the stomach during digestion may act in a similar manner to dioxin, a very potent toxin. Therefore, it is advantageous to produce glucoraphanin-containing preparations containing as little residual indole glucosinolates, or other adverse compounds, as possible.
Several patents describe the development of highly chemoprotecant crucifer germplasm with a significantly improved ratio of glucoraphanin to indole glucosinolates (increasing the ratio from about 0.2 to ˜30). See, e.g., U.S. Pat. Nos. 6,521,818, 6,242,018, 6,177,122, 5,968,567, 5,968,505 and 5,725,895; however, developing the germplasm from laboratory to field trials to market will require considerable time, upwards of up to 5 years, and with no guarantee of success. Hence, there is a need to provide alternative methods for producing high yields of glucoraphanin with a high ratio of glucoraphanin to indole glucosinolates.